12689021 has 4 divisors (see below), whose sum is σ = 13435452. Its totient is φ = 11942592.

The previous prime is 12689003. The next prime is 12689029. The reversal of 12689021 is 12098621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12098621 = 23 ⋅526027.

It can be written as a sum of positive squares in 2 ways, for example, as 5692996 + 6996025 = 2386^2 + 2645^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12689021 is a prime.

It is a super-2 number, since 2×12689021² = 322022507876882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12689029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 373190 + ... + 373223.

It is an arithmetic number, because the mean of its divisors is an integer number (3358863).

Almost surely, 2^12689021 is an apocalyptic number.

It is an amenable number.

12689021 is a deficient number, since it is larger than the sum of its proper divisors (746431).

12689021 is an equidigital number, since it uses as much as digits as its factorization.

12689021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 746430.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 12689021 is about 3562.1652123393. The cubic root of 12689021 is about 233.2434045741.

The spelling of 12689021 in words is "twelve million, six hundred eighty-nine thousand, twenty-one".